1. Field of the Invention
This invention generally relates to the field of air ventilation systems and more particularly is directed to certain improvements in roof mounted exhaust blowers of the type used with kitchen hoods in commercial kitchens for removing smoke and grease laden air over cooking surfaces.
2. State of the Prior Art
Commercial kitchens, such as in restaurants and fast food outlets, frequently have a ventilation hood over stoves, grills, broilers and the like for collecting and exhausting the smoke and fumes generated by cooking processes. Hot grease-laden air rises into the hood, and is drawn into a duct by means of a motor driven blower mounted on the kitchen roof or adjacent area. The contaminated air is exhausted to the outdoors. Such installations are typically required by local ordinance and are therefore in widespread use. There are different manufacturers of such equipment and designs for the exhaust blowers vary in various details and features from one manufacturer to another, although the general mode of operation is similar.
A frequent problem with many kitchen exhaust blowers is the excessive accumulation of solid or semi-solid grease on various parts of the exhaust blower unit and on the adjacent roof and surrounding surface, creating a significant fire hazard.
Many existing grease exhaust blowers offer only restricted interior access and are difficult to clean and service for removal of accumulated grease. In such cases, the service life of the unit is reduced, and unsanitary conditions and the aforementioned fire hazard are allowed to persist. It it therefore highly desirable to provide kitchen exhaust blower units with easy access to all interior parts to ensure regular and thorough cleaning and servicing for optimum and safe performance.
Another common problem is that grease deposited on the walls of the air discharge scoop, typically found in these blowers for directing the air exhaust stream upwardly into the atmosphere, tends to be washed onto the roof surface by rain and snow precipitation. These discharge scoops usually have a receptacle which collects grease runoff from the scoop. The open scoop also collects large amounts of rain water or snow which likewise fill the grease receptacle. Since the grease tends to float on water, the grease accumulated in the receptacle is first to overflow onto the roof surface. Over a period of time, large puddles of roof top grease have been known to accumulate around exhaust blowers. Accumulated roof top grease is hazardous both from a sanitation and fire prevention point of view; it is unsightly; it can cause structural damage to the roof and building by leaking into cracks and crevices of the roof structure, and makes it more difficult and unpleasant for service personnel to reach the blower unit for servicing and cleaning.
It is therefore an important object in designing this type of equipment to minimize the amount of condensed grease which is ejected or spilled by the blower onto the surrounding roof surface.
A continuing need exist for cleaner, easier to service roof-top kitchen exhaust blowers for commercial kitchens.